feat: 优化代码

app/src/main/res/layout/activity_book_read.xml

@@ -13,7 +13,7 @@
         android:id="@+id/cursor_left"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:contentDescription="@null"
+        android:contentDescription="@string/select_start"
         android:src="@drawable/ic_cursor_left"
         android:visibility="invisible" />
 
@@ -21,7 +21,7 @@
         android:id="@+id/cursor_right"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:contentDescription="@null"
+        android:contentDescription="@string/select_end"
         android:src="@drawable/ic_cursor_right"
         android:visibility="invisible" />
 

app/src/main/res/values/strings.xml

@@ -615,4 +615,6 @@
     <string name="header">页眉</string>
     <string name="main_body">正文</string>
     <string name="footer">页角</string>
+    <string name="select_end">文本选择结束位置</string>
+    <string name="select_start">文本选择开始位置</string>
 </resources>